Coefficient coding harmonization in HEVC

1. A system of encoding and decoding video signals, comprising: (a) a video encoder having a computer processor configured for encoding of video frames; and (b) programming executable on said computer processor for: (i) performing intra-prediction based on neighboring reconstructed values, and/or inter-prediction on said video frames based on motion-estimation and motion-compensation; (ii) executing a transform based on said intra-prediction and/or inter-prediction followed by quantization of transform coefficients, and/or executing inverse quantization followed by an inverse transform which is summed with said intra-prediction or inter-prediction, on said video frames; and (iii) performing entropy encoding on said video frames comprising: (A) converting two dimensional transform units (TUs) into one dimensional TUs based on a mode dependent coefficient scan (MDCS); (B) identifying and encoding a last non-zero transform coefficient position; (C) generating a significance map encoding whether a coefficient is zero or non-zero; (D) wherein said TUs are processed either: (1) during mode dependent coefficient scanning (MDCS) with TUs that are 4×4 or 8×8 horizontal or vertical subject to horizontal or vertical scanning, and the remaining TUs including the up-right diagonal 4×4 and 8×8 TUs are subject to 4×4 sub-block up-right diagonal scanning starting from the top-left corner and traversing through to the bottom-right corner; or (2) during generating significance map both large TUs, and 4×4 and 8×8 TUs with 4×4 sub-block up-right diagonal scans in which the 4×4 sub-block is a coefficient group (CG), are processed with multi-level significance map encoding; wherein said multi-level significance mapping encodes a flag indicating if a coefficient group is all zero or not, and also generates individual significance mapping if the coefficient group has any non-zero coefficients; (E) encoding remaining non-zero transform coefficients; (c) a decoder having a computer processor configured for decoding video frames; and (d) programming executable on said computer processor for performing entropy decoding upon receiving encoded video frames comprising replacement of up-right diagonal scan (RDS), and/or applying multi-level significance map coding during decoding of transform units (TUs).

2. The system recited in claim 1 , wherein said encoder coding units (CUs) have variable sizes depending on video content toward achieving a desired coding efficiency, with said CUs split into smaller prediction units (PUs) and transform units (TUs).

3. The system recited in claim 1 , wherein said transform units (TU) refer to a block of residual data to which said transform is applied that generates transform coefficients.

4. The system recited in claim 1 , wherein said video coding system operates with High Efficiency Video Coding (HEVC) coders.

5. The system recited in claim 1 , wherein said programming is configured to utilize the same coefficient coding for all TUs with up-right diagonal scans.

6. An apparatus for entropy encoding within a video coding device, comprising: (a) an encoder having a computer processor configured for encoding video frames; (b) programming executable on said computer processor for: (i) performing intra-prediction on said video frames based on neighboring reconstructed values, and / or inter-prediction on said video frames based on motion-estimation and motion-compensation; (ii) executing a transform based on said intra-prediction and / or inter-prediction followed by quantization of transform coefficients from said transform; and (iii) performing entropy encoding on said video frames comprising: (A) converting two dimensional transform units (TUs) into one dimensional TUs based on a mode dependent coefficient scan (MDCS); (B) identifying and encoding a last non-zero transform coefficient position; (C) generating a significance map encoding whether a coefficient is zero or non-zero; (D) wherein said TUs are processed either: (1) during mode dependent coefficient scanning (MDCS) with TUs that are 4×4 or 8×8 horizontal or vertical subject to horizontal or vertical scanning, and the remaining TUs including the up-right diagonal 4×4 and 8×8 TUs subject to 4×4 sub-block up-right diagonal scanning which starts from the top-left corner and traverses through to the bottom-right corner; or (2) during generating significance mapping both large TUs, and 4×4 and 8×8 TUs with 4×4 sub-block up-right diagonal scans in which the 4×4 sub-block is a coefficient group (CG), are processed with multi-level significance map encoding; wherein said multi-level significance mapping encodes a flag indicating if a coefficient group is all zero or not, and also generates individual significance mapping if the coefficient group has any non-zero coefficients; and (E) encoding remaining non-zero transform coefficients.

7. The apparatus recited in claim 6 , wherein coding units (CUs) of said encoder have variable sizes depending on video content toward achieving a desired coding efficiency, with said CUs split into smaller prediction units (PUs) and transform units (TUs).

8. The apparatus recited in claim 6 , wherein said transform units (TUs) refer to a block of residual data to which said transform is applied that generates transform coefficients.

9. The apparatus recited in claim 6 , wherein said video coding apparatus operates with High Efficiency Video Coding (HEVC) coders.

10. The apparatus recited in claim 6 , wherein said programming is configured to use the same coefficient coding for all TUs with up-right diagonal scans.

11. An apparatus for entropy decoding within a video decoding device, comprising: (a) a decoder having a computer processor configured for decoding video frames; (b) programming executable on said computer processor for performing entropy decoding upon receiving encoded video frames comprising: (i) converting two dimensional transform units (TUs) into one dimensional TUs based on a mode dependent coefficient scan (MDCS); (ii) decoding a last non-zero transform coefficient position; (iii) decoding a significance map from an encoder as to whether a coefficient is zero or non-zero; (iv) wherein said TUs are processed either: (1) during mode dependent coefficient scanning (MDCS) with TUs that are 4×4 or 8×8 horizontal or vertical subject to horizontal or vertical scanning, and the remaining TUs including the up-right diagonal 4×4 and 8×8 TUs are subject to 4×4 sub-block up-right diagonal scanning which starts from the top-left corner and traverses through to the bottom-right corner; or (2) using multi-level significance maps for both large TUs, and 4×4 and 8×8 TUs with 4×4 sub-block up-right diagonal scans in which the 4×4 sub-block is a coefficient group (CG), wherein said multi-level significance mapping encodes a flag indicating if a coefficient group is all zero or not, and also generates individual significance mapping if the coefficient group has any non-zero coefficients; and (v) decoding remaining non-zero transform coefficients.

12. The apparatus recited in claim 11 , wherein coding units (CUs) of said decoder have variable sizes depending on video content toward achieving a desired coding efficiency, with said CUs split into smaller prediction units (PUs) and transform units TUs).

13. The apparatus recited in claim 11 , wherein said transform units (TUs) refer to a block of residual data to which an inverse-transform is applied.

14. The apparatus recited in claim 11 , wherein said video decoding apparatus operates with High Efficiency Video Coding (HEVC) coders.